Fast-cook technology must address consistent quality, the capability to quickly cook a variety of commercially available raw food-stuffs, cook said food-stuff at a significant time and energy savings, aid the end-user and commercial enterprises to meet the demands of economic operation, rapid order turnaround, preparation cost savings, reduced food waste, as well as support for innovative machine applications such as vending. Prior art machines of this kind were not capable of reliable and consistent fast-cook operation, were limited to proprietary raw food designs to enable quick order to plate turnaround while sacrificing economy, and suffered from inconsistent cooking quality of raw food-stuffs in commercial environments. Additionally prior art did not include the process elements and apparatus designs included in this patent, necessary to reliably monitor and maintain the process temperatures and pressures required to enable consistent cooking quality, nor were prior art designs robust enough for reliable machine operation in a compact package that would function reliably, provide for user-selectable cooking controls, and yet operate with minimal user intervention.
The design of the invention is ideally suited to service the fast food, hospitality and vending industries that require fast cooking of raw food-stuffs in 4 minutes or less, within the confines of a single cooking chamber using superheated water. Superheated water promotes the uniform heating and accelerated hydration for high-speed cooking of the targeted food-stuff.
The raw food-stuff is either automatically or manually introduced into the cook chamber. The cook chamber containing the raw food-stuff is charged with water superheated above 100 degrees Celsius and pressurized. Using process control circuitry, sensors, smart heating elements and software, the process is more efficiently and reliably managed. When cooking has proceeded for a pre-set period of time, at controlled temperatures and pressures, the chamber is decompressed, the cooked product rinsed with cooler water below 100 degrees Celsius, and then discharged into the food collection strainer. Process control includes sensors to monitor both temperature and pressure in the boiler and cook chamber, includes feedback loops to modulate both the temperature and pressure of the water contained within the boiler and in cook chamber, and proprietary programming to take advantage of control timers, counters, switches, relays, timer relays and other soft and hard devices to enable a precise sequence of operation and control. Temperatures and pressures are adjustable, monitored and controlled to maintain consist cooking throughout the cook cycle. Once cooked, rinsed and discharged, the food-stuff is emptied from the strainer and the strainer reinserted. The machine is then ready for the next cooking cycle.
It is another advantage of the invention to incorporate a cooking chamber and water boiler that are housed within a sealed enclosure containing a heat transfer fluid. The heat transfer fluid is used to convey heat from the heating elements immersed in the contained fluid. The heat transfer fluid bathes the outer walls of the boiler and cook chambers. The cooking assembly enclosure containing the heat transfer fluid is not pressurized and is protected from any pressurization due to fluid expansion by added volumetric capacity within the vessel, redundant temperature controls, and pressure relief. The volumetric capacity of the cooking assembly enclosure surrounding the boiler and cook chamber is designed to contain sufficient heat transfer fluid to provide a heat reservoir, which reduces the time necessary to heat the water contained within the boiler, provides heat to maintain the cook chamber temperature without the use of heating elements internal to the cook chamber, replaces heat lost during the cooking process, and compensates for any extraneous conductive, convective and radiant heat losses, while providing this make up heat quickly enough to ready the process for the subsequent cooking cycle without delay. The cooking assembly is comprised of an enclosure sealably attached to the cooking assembly top and bottom end plates that complete the enclosure. The end plates are fabricated with multiple penetrations and porting. One or multiple heating elements are mounted through the plates and into the heat transfer fluid to provide the quantity of energy necessary to heat the heat transfer fluid to design process temperatures.
The number of elements used is determined by the size of the fluid chamber, the heating demand of the cook chamber, measured and calculated heat losses, the thermal characteristics of the heat transfer fluid, heat transfer enclosure surface area, materials of construction, and insulation. One or more additional heating elements reside within the boiler and provide additional heating to quicken the elevation of the boiler water to its superheated target temperature.
The superheat boiler and the cook chamber are designed to function as pressure vessels that normally operate at a pressure range of 350 psi and up to but not to exceed a normal operating pressure of 500 psi at design operating temperatures. Safety factors are used in the design of the apparatus. Design temperature of the device is to operate at a temperature of 350 Fahrenheit and under normal operations up to but not to exceed 500 Fahrenheit. These operating conditions are controlled, balanced and maintained by process control circuits, redundant sensors with safety backups and programming. Cooking is by superheated water and not steam and the equipment and process control is designed to prevent significant steam generation during the cooking cycle. Temperature and pressure are adjusted by programming to tailor the operation of the device to the most efficient temperature and pressure to speed-cook the desired raw food-stuff.
Supply water is pumped into the boiler up to a pre-set pressure using a pressure pump. Once heated within the boiler, the superheated water is transferred from the boiler to the cook chamber and the pressure in the cook chamber is boosted by a second pressure pump that can operate at design temperatures and reliably increase the superheated water in the cook chamber to the design pressures. This second pressure pump also maintains the cook chamber pressure for the duration of the cook cycle. Water flows into the boiler and cook chamber by fluid conduits and flow is regulated by process controlled solenoid valves.
It is another advantage of the invention to incorporate unique process control and automation including unique proprietary slide plate valve technology, positional feedback of the proprietary slide plate valves, surface temperature controlled heating elements that limit the outside skin temperature of the elements, and their use immersed in the heat transfer fluid and within the boiler. The heating elements are controlled by independent temperature probes and process control circuits. The heating element surface temperature is independently controlled by built-in limiters, which prevent the skin temperature from exceeding a pre-set temperature. High skin temperature promotes heat transfer fluid degradation and charring, and boiler over-pressurization and steam formation. The proprietary nature of the cooking chamber inlet and discharge slide plate valves include the overall design, sealing design, sealing methodology, slide plate supports and surface finishes. The valves use a sealing design that increases sealing force as process pressure increases, providing a positive and reliable seal. The design allows for an increase in sealing force without significantly increasing the motor force necessary to actuate the valve and linearly reposition the valve plate to and from the target position.
The pumps, solenoid valves, slide plate valves including associated drives, and the self-regulating heating elements are controlled by proprietary programmable process control circuits. The process control circuits are capable of factory and user input to change key operating criteria and provides selected data output and usage statistics. The programmable process control circuits utilize sensors that detect water temperature, heat transfer fluid temperature, boiler and cook chamber pressures, and slide plate position. Safety devices include pressure relief, redundant temperature probes, pressure transducers, and pressure switches. Operator safety dictates that the device be connected to main power using GFI circuit protection. All operator capable access points are restricted by design. These components are interlocked and electronically monitored for presence by the process control circuit.